This application is based on Patent Application No. 11-153061 (1999) filed May 31, 1999 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to an ink-jet printing apparatus, an ink-supplying apparatus, and a method for supplying ink.
2. Description of the Related Art
There are several systems for supplying ink to an ink-jet printing apparatus, such as a so-called on-carriage tank system, tube system, and on-demand systems.
The on-carriage tank system, in a serial-scan type printing apparatus, supplies ink to a printing head mounted on a carriage from an ink tank mounted on the carriage. The tube system supplies ink from an external ink tank to a printing head through a tube that connects them together. In this case, the external ink tank is placed on the outside of the carriage. Furthermore, the on-demand type system supplies ink from a second ink tank provided on the body of a printing apparatus to a first ink tank provided on the carriage by connecting them together at the time of ink-supply.
An example of the ink tank to be used in the on-carriage tank system is the one integrally provided with a printing head. Alternatively, another example of such an ink tank is one removably connected to the printing head. The removable ink tank can be removed from the printing head and replaced with new one, so that it is possible to keep the printing head in place without throwing away and to carry out a reduction of running costs. In the on-carriage tank system using such an ink tank, the frequency of replacing the ink tanks should be reduced for reducing the running costs and reducing the burdens on the operator. In this case, however, the capacity of the ink tank should be increased, proportionally resulting in the incrementing of the carriage weight, upsizing of the body of the apparatus, and enhancement of both the carriage-driving and carriage-driving parts.
In the tube system, furthermore, the tube applies a large load on the movement of the carriage. In particular, recently, the weight of the ink-supplying portion tends to be increased because the tube that allows the increased supply of ink is required as printing speed increases. In addition, the tube may be curved due to the movement of the carriage, so that an image formation may be unevenly performed as a result of the variations in the pressure of supplying ink. The necessity to make a large pressure for supplying ink to fill the tube with ink in the case of filling an empty tube with ink at an early stage of the ink-supply. Moreover, there is a problem that it takes much time and so on.
For solving the problems of both the on-carriage tank system and tube system, another system of the ink supply is suggested. In the system, an ink tank (an on-carriage ink tank) of the side of carriage and an ink tank on the side of printing apparatus is connected together only when required to supply ink. Ink is supplied from the latter ink tank to the former ink tank.
In the meantime, whatever an ink-supplying system may be, in the case where an ink-supplying timing is set when the ink residue in the ink tank decreases to predetermined quantity, the following problems occur.
That is, for example, when an ink-supplying timing is generated during image printing operation using a printing head, the printing operation is suspended, and ink must be supplied. During ink-supplying operation, image printing operation is impossible, and thus, a nominal printing speed is lowered. Before and after ink supply, there may occur a remarkable difference in permeation of the ink ejected on the printing medium. In this case, band-shaped printing non-uniformity is generated on a printing image.
An object of the present invention is to provide an ink-jet printing apparatus, an ink-supplying device, and a method for supplying ink, where the manner of ink supply is modified so that an image formation is performed at a high printing rate.
In a first aspect of the present invention, there is provided an ink-jet printing apparatus for printing an image on a printing medium using an ink jet printing head that is capable of eject ink supplied from an ink tank, comprising:
ink-supplying means that is capable of supplying ink to the ink tank;
detecting means for detecting the time of ink-supply as the ink tank requires the supply of ink; and
control means that makes a change to a mode of supplying ink to the ink tank by the ink-supplying means in accordance with the status of actuating the ink-jet printing apparatus at the time of ink-supply which is determined by the detecting means.
In a second aspect of the present invention, there is provided an ink-supplying apparatus to be actuated in relation to the operation of an ink-jet printing apparatus that performs an image formation on a printing medium using an ink-jet printing head that is capable of ejecting ink to be supplied from an ink tank, comprising:
ink-supplying means that is capable of supplying ink to the ink tank;
detecting means for detecting the time of ink-supply as the ink tank requires the supply of ink; and
control means that makes a change to a mode of supplying ink to the ink tank by the ink-supplying means in accordance with the status of actuating the ink-jet printing apparatus at the time of ink-supply which is determined by the detecting means.
In a third aspect of the present invention, there is provided a method for supplying ink, which is related to the operation of an ink-jet printing apparatus that performs an image formation on a printing medium using an ink-jet printing head that is capable of ejecting ink to be supplied from an ink tank, comprising:
an ink-supplying means that is capable of supplying ink to the ink tank; and comprising the steps of:
detecting the time of ink-supply as the ink tank requires the supply of ink; and
making a change to a mode of supplying ink to the ink tank by the ink-supplying means in accordance with the status of actuating the ink-jet printing apparatus at the time of ink-supply.
The present invention is configured such that the manner of ink supply is changed in accordance with the time when the supply of ink to an ink tank is required. This offers an advantage of being able to perform the action of ink supply so as to appropriately fit to the operating status of the ink-jet printing apparatus. Therefore, it is possible to increase the printing rate.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.